If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

This comes to us from BimmerBoost sponsor Burger Tuning (BMS) who decided to put together a few dyno charts showing the difference between the stock N54 twin turbochargers maxed out, upgraded twin turbos, and the single turbo conversion. These all come from a E9X 335i with an automatic transmisison. As one would expect, the single turbo shifts the powerband to the right making for more peak horsepower but less torque through the entire curve and down low compared to the upgraded twins.

More insight from Terry@BMS:

A couple interesting charts to check out.

The first is maxed out OEM turbos compared with RBs. Both done on the same car a few months apart.

The second is RBs compared with a single turbo running higher octane and meth. It's an interesting comparison with the single as both cars are automatic so you get an apples to apples feeling for the power curves.

The single turbo clearly has the edge from 5700-6500rpm but for all around street car use does that gain make up what is lost below 4000rpm? In terms of racing I'd love to see what the 335 auto single runs 60-130. Is it going to be in the 6s or are we looking more like low 7s? Our 135 is around 140# lighter, but makes maybe an average of 35whp less from 5700rpm+ to redline, so I'm curious just how far behind it would wind up. Hopefully I can get some 60-130 testing on ours done this weekend.

well, you've got a couple advantages there beginning with a car that is actually running! heh

Well I did one trial run in 75 degree weather and got a 7.58 on a 1.48% slope. So I think I took your record, lol. That auto shift right at 130mph kills it. Going to pump the tires up a bit more and see if I can squeeze another mph out of them to avoid the shift. If not I'll need to grab maybe 1/2" taller tires. Next run will be in colder weather too.

Well I did one trial run in 75 degree weather and got a 7.58 on a 1.48% slope. So I think I took your record, lol. That auto shift right at 130mph kills it. Going to pump the tires up a bit more and see if I can squeeze another mph out of them to avoid the shift. If not I'll need to grab maybe 1/2" taller tires. Next run will be in colder weather too.

shiiit.. thats nothin to worry about, youll be in 6's in no time,
.5 in the slope is good for .5 in the 130

Well I did one trial run in 75 degree weather and got a 7.58 on a 1.48% slope. So I think I took your record, lol. That auto shift right at 130mph kills it. Going to pump the tires up a bit more and see if I can squeeze another mph out of them to avoid the shift. If not I'll need to grab maybe 1/2" taller tires. Next run will be in colder weather too.

Hi Terry - I see you've upgraded the 1 a bit !!! 7.5's are no joke in warm weather.

It appears to me that the BMW community is really prepping nicely for the Airstrip Event...with a lot of people making significant upgrades since the last one. See you there!